Acute myelogenous leukemia (AML) is the second most common leukemia in children, with ~400 new cases occurring annually in the United States. Worldwide, the highest rates of childhood AML occur in Asia and the lowest rates are reported from India and South America. Numerous genetic risk factors for childhood AML have been defined, including Down syndrome, neurofibromatosis, and Fanconi anemia. Research into environmental risk factors has been limited by the rarity of this disease; however, studies of AML in adults have implicated ionizing radiation, solvents, and petroleum products as potential etiologic agents. The largest analytic study of childhood AML found that occupational exposures of either parent to pesticides, paternal exposure to petroleum products, and postnatal exposures to pesticides are increased in children with AML. In addition, maternal use of marijuana during pregnancy was associated with an increased risk of AML, especially the monocytic subtypes. Further study of childhood AML, including occurrence of the disease as a second malignancy, is needed in order to confirm these findings and to increase our understanding of this leukemia. © 1995 Raven Press, Ltd., New York.